The field of this invention is that of inserting and retrieving several thousand feet of a flexible hose from a horizontal opening into the narrow annulus between casing strings of oil or gas wells. The hose will be inserted through the wellhead outlet bore that has relatively sharp corners at the annulus opening. The hose bend radius required at the annulus opening where the casing annulus and the wellhead outlet bore intersect is a very tight turn requiring the hose to turn from horizontal to vertical in the distance of approximately 1.25 inches. When hoses are inserted they are cut or crimped by the sharp corners at the annulus opening (intersection) and are rendered useless and/or can not be retrieved because they will be severed by the sharp corners. The hose may be attached to a specialized weight system to facilitate its downward movement once inside the annulus. The hose can be fitted with a check valve to eliminate the back flow of pressure.
Once inserted and positioned in the annulus the hose can inject anti-freeze type chemicals to eliminate hydrate formation or inject designed weight fluids to produce the desired hydrostatic head pressure to reduce the influx of unwanted fluids from outside the casing. Then once the job is complete the hose can not be recovered however, it would be desirable to recover the hose for use else where if possible.
Oil or gas wells can encounter problems with the formation of hydrates (a form of ice) in the casing annulus. The formation of hydrates in a confined space can generate a pressure of several thousand pounds per square inch. The casing annulus is a confined space therefore the expansion pressure encountered during the formation of hydrates can cause the internal casing to collapse or the external casing to burst. Both forms of damage are difficult and costly to repair.
Oil or gas wells can encounter problems when the casing develops a hole or the cement job becomes porous and unwanted fluids begin to infiltrate and pressurize the casing annulus. This infiltration results when an infiltration path is created and the casing annulus contains a lower pressure than the outside reservoir or other casing strings.